Control mechanism for steerable rod

ABSTRACT

The present invention relates to a control mechanism for controlling a rod (210) having at least one key, the control mechanism comprising a handle comprising a sliding ring (131), a sliding shaft (132) and a drive shaft (133), each extending along a longitudinal axis (101) and comprising a central opening; and a friction reduction cannula (110) comprising an opening configured to receive the rod (210). The present invention also relates to a steerable device and a steerable system comprising the control mechanism according to the invention.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a national phase entry under 35 U.S.C. § 371of International Application No. PCT/EP2016/071922 filed Sep. 16, 2016,published in English, which claims priority from French PatentApplication No. 1558697 filed Sep. 16, 2015, both of which areincorporated herein by reference in their entirety.

FIELD OF INVENTION

The present invention pertains to the field of medical devices, inparticular orthopedic devices. The invention especially relates toimproved mechanisms for controlling a rod used for creating cavities intissue.

BACKGROUND OF INVENTION

Vertebral compression fractures involve the collapse of one or morevertebral bodies in the spine. Vertebral compression fractures orrelated spinal deformities may initiate, for instance, from metastaticdiseases, injuries or osteoporosis.

Conventional surgery for treating vertebral compression, often referredto as vertebroplasty, includes a cannula or a needle inserted throughthe posterior of a targeted vertebral body, usually through thepedicles. Once positioned within the compressed vertebral body, bonecement is pushed through the needle into the vertebral body. Variationsof vertebroplasty include the deployment of mechanical devices orexpansion of a balloon to restore the height of the vertebral body andto create a void in a compressed vertebral body; bone cement is theninserted into the space to stabilize the devices and to strengthen thevertebral body.

In order to sufficiently access a vertebral body for complete infusionof cement it is known to use curved needle enabling interdigitation ofthe cement.

Such curved needles are often made of shape-memory alloys. For instance,WO 00/33909 discloses a needle assembly comprising a hollow, curved,superelastic infusion needle. The needle assembly comprises an infusionneedle made of a superelastic material such as nitinol and an outercannula for introduction into the body of a patient. The said rigidouter cannula is required as the initial access to the vertebral bodymust be made using a relatively straight approach. Upon deployment fromthe outer cannula, the needle cannula substantially returns to thepreformed curved configuration for the introduction of materials atareas lateral to the entry path of the needle assembly. In order toavoid coring the bone tissue during introduction, a trocar is insertedinside the outer cannula during introduction; once the outer cannula hasbeen directed to the target site, the trocar is removed and the infusionneedle is inserted into the said outer cannula.

However, with such devices, the friction between the curved needle andthe outer cannula prevents easy introduction of the curved needle. As aresult, there is a need for device creating voids within tissue withreduced friction during insertion between the curved needle or rod andthe outer cannula directed to the target site.

WO2014/093464 discloses a friction reduction covering sized to bereceived in a cannula and a cavity creation member, biased from aretracted to a deployed configuration, sized to be disposed in thefriction reduction covering. With such devices, the curved needle isenclosed within a rigid covering. Consequently, there is reducedfriction between the curved needle and the cannula during the surgicalprocedure. However, within WO2014/093464 the friction reduction coveringis not secured to the handle and slides freely in at least onedirection.

Therefore there is still of need for improved control of the deploymentof the curved needle relative to the handle and/or the frictionreduction covering.

SUMMARY

To this end, the present invention relates to a mechanism forcontrolling rods used for creating cavities in tissue. The controlmechanism may further be used for injecting material within said cavity.The present invention also relates to steerable devices for creatingcavities and injecting material in tissue, the said devices comprisingthe control mechanism of the invention and the rod.

The present invention thus relates to a control mechanism forcontrolling a rod having a preformed bent and at least one key, thecontrol mechanism comprising:

-   -   a handle comprising a sliding ring, a sliding shaft and a drive        shaft, each extending along a longitudinal axis and comprising a        central opening; wherein    -   the sliding ring is threadedly connected to the sliding shaft;    -   the drive shaft and the sliding shaft are connected by blocking        means which prevent axial rotation between the drive shaft and        the sliding shaft and which allow the drive shaft to slide        within the sliding shaft; and    -   the drive shaft and the sliding ring are connected by connecting        means which prevent axial displacement between the drive shaft        and the sliding ring and which allow axial rotation between the        drive shaft and the sliding ring; and    -   the internal surface of the drive shaft comprises at least one        longitudinal groove or keyseat configured to engage the at least        one key of the rod; and    -   a friction reduction cannula configured to receive the rod;        wherein the friction reduction cannula is secured to the sliding        shaft or to the drive shaft.

According to one embodiment, the sliding ring comprises a threaded innersurface and the sliding shaft comprises at least one protrusionprotruding outwardly from the sliding shaft and engaging the at leastone threaded inner surface of the sliding ring so that axial rotation ofthe sliding ring causes the sliding shaft to move back and forth alongthe longitudinal axis.

According to one embodiment, the blocking means comprise at least onekey or at least one longitudinal keyseat within the external surface ofthe drive shaft engaged in respectively at least one longitudinalkeyseat or at least one key within the internal surface of the slidingshaft.

According to one embodiment, the connecting means between the driveshaft and the sliding ring comprise a bearing such as a plain bearing.

According to one embodiment, the friction reduction cannula has alongitudinal axis and comprises an opening configured to receive andrestrain at least partially the rod, especially the preformed bent, in astraight configuration along the longitudinal axis.

According to one embodiment, the friction reduction cannula is made fromsteel, preferably stainless steel.

According to one embodiment, the friction reduction cannula comprises aproximal part and a distal part, wherein the distal part is moreflexible than the proximal part so that the proximal part restrains therod in the straight configuration and the distal part does not restrainthe rod in the straight configuration.

According to one embodiment, the proximal part of the friction reductioncannula is made from steel, such as stainless steel and a distal part ismade from a polymeric material such as polyether block amide.

According to one embodiment, the drive shaft further comprises at itsproximal end a connecting thread.

According to one embodiment, the control mechanism further comprising aconnecting cap comprising a threaded inner surface assembled onto theconnecting thread, the said connecting cap comprising a plurality offlexible lugs, protruding distally and outwardly, designed to engage aplurality of openings at or near the proximal end of the sliding ringthereby preventing rotation of the sliding ring.

According to one embodiment, the connecting cap further comprises atleast one protrusion or recess, preferably a sawtooth protrusion or asawtooth recess.

According to one embodiment, the sliding shaft further comprises a hubprotruding distally and outwardly.

According to one embodiment, the hub comprises a locking ring designedto secure the sliding shaft with a trocar.

The present invention also relates to a steerable device comprising acontrol mechanism according to the invention and a rod having apreformed bent and at least one key, the rod being preferably made froma superelastic material, such as an alloy of nickel and titanium.

According to one embodiment, the angle of deflection of the rod rangesfrom 20° to 150°, preferably from 30° to 130°, more preferably from 40°to 110°.

According to one embodiment, the rod comprises at its proximal end aknob comprising a threaded inner surface designed to be assembled ontothe connecting cap, the knob and the rod being connected by means of abearing which allow axial rotation between the knob and the rod.

According to one embodiment, the knob further comprises at least oneprotrusion or recess, preferably a sawtooth protrusion or a sawtoothrecess designed to be engaged with respectively at least one recess orprotrusion of the connecting cap thereby preventing rotation between theconnecting cap and the knob.

The present invention also relates to a steerable system comprising asteerable device according to the present invention and a trocar,preferably a bone access trocar, suitable to be positioned adjacent toan exterior surface of a targeted tissue.

According to one embodiment, the steerable device, especially thefriction reduction cannula, is inserted in the trocar and connected bythe locking ring. According to an alternative embodiment, the trocar isthreadedly connected to the hub.

According to one embodiment, the control mechanism comprises a frictionreduction cannula made from steel, preferably stainless steel.

Definitions

In the present invention, the following terms have the followingmeanings:

-   -   As used herein the singular forms “a”, “an”, and “the” include        plural reference unless the context clearly dictates otherwise.    -   The term “about” is used herein to mean approximately, roughly,        around, or in the region of. When the term “about” is used in        conjunction with a numerical range, it modifies that range by        extending the boundaries above and below the numerical values        set forth. In general, the term “about” is used herein to modify        a numerical value above and below the stated value by a variance        of 20 percent, preferably of 5 percent.    -   The words “proximal” and “distal” refer to directions        respectively towards and away from the surgeon using the medical        device.    -   “Rod” or “Steerable rod” refers to a rod or bar comprising a        part having a predefined bent or curvature.    -   “Secured” means attached, coupled or connected in a        non-detachable manner unintentionally. Therefore, the term        secured may comprise for instance the term integrally connected        or over-molded.    -   “Tissue” refers herein to soft tissue or hard tissue. According        to a preferred embodiment, tissue refers to hard tissue such as        bone tissue.

DETAILED DESCRIPTION

The following detailed description will be better understood when readin conjunction with the drawings. For the purpose of illustrating, thedevice is shown in the preferred embodiments. It should be understood,however that the application is not limited to the precise arrangements,structures, features, embodiments, and aspect shown. The drawings arenot drawn to scale and are not intended to limit the scope of the claimsto the embodiments depicted.

According to a first aspect of the invention, there is provided acontrol mechanism for controlling a rod used for creating cavities intissue, comprising a friction reduction cannula and a handle.

As depicted in FIG. 1, the control mechanism 100 elongates along alongitudinal axis 101 between a proximal end 100 a and a distal end 100b spaced apart from the proximal end 100 a. The control mechanism 100comprises a friction reduction cannula 110 and a handle 130.

As depicted in FIGS. 2, 3 and 4, the handle 130 is configured to begrasped by the user and comprises a sliding ring 131, a sliding shaft132 and a drive shaft 133. The handle 130 extends along a longitudinalaxis 101 from a proximal end to a distal end.

The sliding ring 131 is cylindrical or tubular, extends along alongitudinal axis 101 and comprises a central opening from a proximalend 131 a to a distal end 131 b. According to one embodiment, thecentral opening is configured to receive the sliding shaft 132 and thedrive shaft 133. According to one embodiment, the sliding ring 131,especially the central opening comprises a threaded inner surface.According to one embodiment, the threaded inner surface of the slidingring 131 is a cylindrical surface formed with a continuous thread.

The sliding shaft 132 is cylindrical or tubular, extends along alongitudinal axis 101 and comprises a central opening from a proximalend 132 a to a distal end 132 b. According to one embodiment, thecentral opening is configured to receive a drive shaft 133. According toone embodiment, the sliding ring 131 is cylindrical and is outside andencloses at least partially the sliding shaft 132. According to oneembodiment, the sliding shaft 132 comprises at least one tab, pin orprotrusion 1321 extending outwardly, preferably at the proximal endthereof 132 a. According to one embodiment, the outer surface of thesliding shaft 132 comprises marks indicating the translation of thesliding ring 131 relative to the sliding shaft 132.

The sliding ring 131 is threadedly connected to the sliding shaft 132.According to one embodiment, the protrusion(s) 1321 of the sliding shaft132 engage or mate with threaded inner surface of the sliding ring 131.More particularly, the external protrusion(s) 1321 of the sliding shaft132 is engaged with the internal thread of threaded inner surface of thesliding ring 131. Rotation of the sliding ring 131 causes sliding shaft132 to move relatively along a helical path of the thread of threadedinner surface of the sliding ring 131. More particularly, rotation ofthe sliding ring 131 causes protrusions 1321 of the sliding shaft 132 totrack the helical path of the thread of threaded inner surface of thesliding ring 131. So, rotation about the longitudinal axis of thesliding ring 131 causes the sliding shaft 132 to move back and forthalong the longitudinal axis 101, relative to the sliding ring 131. Withrespect to the sliding shaft 132, rotation of the sliding ring 131causes the sliding ring 131 to move back and forth along thelongitudinal axis 101 in rotation.

According to an alternative embodiment wherein the sliding ring isthreadedly connected to the sliding shaft; the sliding shaft 132comprises a threaded outer surface and the sliding ring comprises an atleast one tab, pin or protrusion extending inwardly, preferably at thedistal end thereof and engage the threaded outer surface of the slidingshaft.

The drive shaft 133 is cylindrical or tubular, extends along alongitudinal axis 101 and comprises a central opening from a proximalend 133 a to a distal end 133 b. According to one embodiment, thesliding shaft 132 is cylindrical and is outside and encloses at leastpartially the drive shaft 133. According to one embodiment, the driveshaft 133 is configured to slide longitudinally inside the sliding shaft132.

According to one embodiment, the drive shaft 133 and the sliding shaft132 are connected by blocking means which prevent axial rotation betweenthe drive shaft 133 and the sliding shaft 132 and which allow the driveshaft 133 to slide within the sliding shaft 132. According to oneembodiment, the drive shaft 133 comprises at least one key sliding in akeyseat, such as at least one longitudinal slot, in the internal surfaceof the sliding shaft 132. Alternatively, the sliding shaft 132 comprisesat least one key sliding in a keyseat, such as at least one longitudinalslot, in the external surface of the drive shaft 133. Consequently, thedrive shaft 133 is prevented from rotating axially relative to saidsliding shaft 132.

According to one embodiment, the drive shaft 133 is connected to thesliding ring 131 by means of a connecting means, such as shoulders andgrooves. According to one embodiment, the said connecting means form abearing, such as a plain bearing. According to one embodiment, thebearing allows axial rotation of the sliding ring 131 relative to thedrive shaft 133 about the longitudinal axis of the rod. According to oneembodiment, the bearing prevents any other degrees of freedom. Accordingto one embodiment, the drive shaft 133 is connected with the slidingring 131 by means of a bearing which prevents axial displacement betweenthe drive shaft 132 and the sliding ring 131 and which allows axialrotation between the drive shaft 132 and the sliding ring 131.Consequently, as the threads of the sliding ring 131 track theprotrusions(s) 1321 of the sliding shaft 132, driving the sliding ring131 into a helical path, the drive shaft 133 translates in alongitudinal axis relative to the sliding shaft 132. According to oneembodiment, the drive shaft 133 and the siding ring 131 are connectedtogether at or near their proximal end 131 a, 133 a.

According to one embodiment, the proximal end 133 a of the drive shaft133 comprises a connecting thread 1331, protruding proximally. In oneembodiment, the said connecting thread 1331 is any connecting threadknown by one skilled in the art such as a “luer” type allowingconnections of multiple devices equipped with mating threads.

According to one embodiment, the handle 130 comprises a connecting cap135 comprising an inner thread so that the connecting cap 135 can beassembled onto the connecting thread 1331. According to one embodimentthe connecting cap 135 comprises a plurality of flexible lugs 1351protruding outwardly and distally. Said flexible lugs 1351 engage aplurality of openings at or near the proximal end 131 a of the slidingring 131 thereby preventing rotation of the sliding ring. Consequentlywhen the connecting cap 135 is assembled onto the connecting thread1331, the sliding ring 131 cannot axially rotate about the longitudinalaxis 101 relative to the sliding shaft 132. According to one embodiment,the outer surface of the connecting cap 135 comprises a thread.

According to one embodiment, the sliding shaft 132 comprises a hub 1322extending distally and outwardly from the sliding shaft 132. Accordingto one embodiment, the connection between the hub 1322 and the slidingshaft 132 prevents any degrees of freedom. According to one embodiment,the sliding shaft 132 and the hub 1322 are integral. According to oneembodiment, the handle 130, especially the sliding shaft 132, moreparticularly the hub 1322, comprises arrows pointing to the samedirection.

According to one embodiment, the handle 130 may be manipulated from aretracted position to a deployed position. In the retracted position,the protrusion(s) 1321 of the sliding shaft 132 engage the distal end ofthe thread of the sliding ring 131, as depicted in FIGS. 5, 6 and 9. Inthe deployed configuration, the protrusion 1321 of the sliding shaft 132engage the proximal end of the thread of the sliding ring 131 asdepicted in FIGS. 7,8 and 9.

As depicted in FIG. 1, the friction reduction cannula 110 extends alonga longitudinal axis 101. The friction reduction cannula defines aproximal end 110 a and a distal end 110 b that is spaced apart from theproximal end 110 a along the longitudinal axis. The friction reductioncannula 110 also defines an outer cannula surface and an inner cannulasurface opposite the outer cannula surface. The inner cannula surfacedefines a cannula opening elongating along the longitudinal axis betweenthe proximal end 110 a and the distal end 110 b.

According to one embodiment, the cross-sectional section of the innercannula surface of the friction reduction cannula 110 is constant alongthe longitudinal axis. According to one embodiment, as depicted in FIGS.10, 11 and 12; the friction reduction cannula opening is configured andsized to receive at least a portion of a rod 210. The friction reductioncannula 110 is configured to enclose at least partially a rod 210 asdepicted in FIGS. 10, 11 and 12.

According to one embodiment, when used with a rod 210, the frictionreduction cannula 110 is configured to restrain at least partially therod 210 in a straight configuration along the longitudinal axis in orderto ease insertion of the rod within a trocar 310, such as a bone accesstrocar. According to one embodiment, the friction reduction cannula 110is configured to be used coaxially with the rod 210 for restraining atleast partially the rod 210 is a straight configuration along thelongitudinal axis.

According to one embodiment, the cross-sectional section of the outercannula surface of the friction reduction cannula 110 is constant alongthe longitudinal axis. According to one embodiment, the frictionreduction cannula opening is configured and sized to be received in atleast a portion of a trocar 310, such as a bone access trocar. Thetrocar 310 is configured to enclose at least partially the frictionreduction cannula 110 as depicted in FIG. 4.

According to one embodiment, the handle 130 further comprises lockingmeans configured to connect a trocar 310, sized to enclose at leastpartially the friction reduction cannula 110, to the handle 130. Asdetailed hereafter, said locking means may be positioned on the hub 1322and may be a locking ring 1323 or any connecting thread.

According to one embodiment, as depicted in FIGS. 2 and 3, the frictionreduction cannula 110 is secured to drive shaft 133. According to apreferred embodiment, the proximal end of the friction reduction canula110 a is secured to distal end 133 b of the drive shaft 133. In oneexemplary embodiment, the drive shaft 133 is molded over the frictionreduction cannula 110. According to one embodiment, the frictionreduction cannula 110 and the drive shaft 133 are connected by anO-ring.

According to an alternative embodiment, as depicted in FIGS. 16, 17 and18, the friction reduction cannula 110 is secured to the sliding shaft132, especially with the hub 1322. According to a preferred embodiment,the proximal end of the friction reduction cannula 110 a is secured tothe distal end of the sliding shaft 132 b, especially with the hub 1322.

According to one embodiment, as depicted in FIG. 11, the frictionreduction cannula 110 comprises a proximal part 111 and a distal part112. According to one embodiment, the distal part of the frictionreduction cannula 112 is more flexible than the proximal part of thefriction reduction cannula 111. According to one embodiment, theproximal part of the friction reduction cannula 111 is made from steel,preferably stainless steel. According to one embodiment, the distal partof the friction reduction cannula 112 is made from polymeric material,such as polyether block amide. According to one embodiment, the ratiobetween the length along the longitudinal axis of the distal part 112and the length along the longitudinal axis of the proximal part 111 isranging from ½ to ⅙. According to one embodiment, when used with a rodhaving a predefined bent, the distal part of the friction reductioncannula 112 has a length equal to the length of the bent part of the rod210.

According to one embodiment, when used with a rod 210 having apredefined bent, the proximal part of the friction reduction cannula 111is configured to restrain the rod 210 in a straight configuration whenthe distal end 210 b of the rod does not extend out distally from theproximal part 111. According to one embodiment, the distal part of thefriction reduction cannula 112 is not configured to restrain the rod 210in a straight configuration when the distal end 210 b of the rod 210extends out distally from the proximal part 111; the distal part 112follows the curvature of the rod 210.

According to one embodiment, when the friction reduction cannula 110 issecured to the drive shaft 133, the friction reduction cannula is madeof two parts: a proximal part 111 and a distal part 112 more flexiblethen the proximal part.

According to one embodiment, in order to avoid that the distal part 112shrinks during insertion in the tissue, the distal part comprises metalreinforcements. According to one embodiment, the polymeric material ofthe distal part 112 is over-molded on the metallic reinforcements.

According to an alternative embodiment, the friction reduction cannula110 is made in a single piece. According to said embodiment, thefriction reduction cannula 111 is made from steel, preferably stainlesssteel.

According to one embodiment, when used with a rod 210, the frictionreduction cannula 110 is configured to restrain the rod 210 in astraight configuration when the distal end of the rod 210 b does notextend out distally from the friction reduction cannula 110.

According to one embodiment, when the friction reduction cannula 110 issecured with the sliding shaft 132, the friction reduction cannula 110is made in a single piece.

According to a second aspect of the invention, there is also provided asteerable device for creating cavities and injecting material in tissueusing minimally invasive techniques.

The steerable device 200 according to the invention comprises thecontrol mechanism 100 of the invention and a rod 210. The rod 210 passesthrough the drive shaft 133 and the sliding shaft 132 of the controlmechanism 100.

According to one embodiment, the rod 210 has a predefined bend.According to one embodiment, only the distal part of the rod is bent,preferably from 1 to 50%, preferably from 2 to 25%, more preferably from5 to 10% of the length of the rod 210. According to said embodiment, theproximal part of the rod 210 extends along a longitudinal axis 101. Therod 210 defines a proximal end 210 a and a distal end 210 b that isspaced apart from the proximal end 210 a According to one embodiment,the angle of deflection of the rod 210 ranges from 20° to 150°,preferably from 30° to 130°, more preferably from 40° to 110° (asmeasured from the longitudinal axis). According to one embodiment, thecross-sectional section of the rod 210 is constant. According to oneembodiment, the rod 210 has no opening along its length.

According to one embodiment, the length of the rod 210 along thelongitudinal axis 110 is equal to the length along the longitudinal axis110 from the proximal end of the handle 130 to the distal end of thefriction reduction cannula 110 b.

According to one embodiment, the rod 210 comprises a superelasticmaterial, preferably an alloy of nickel and titanium.

According to one embodiment, the rod 210 comprises a knob 211 at itsproximal end 210 a. According to one embodiment, the knob 211 is free inrotation relative to the rod 210. According to one embodiment, the rod210 is connected to the knob 211 by means of a bearing, such as a plainbearing. According to one embodiment, the bearing allows axial rotationof the knob 211 relative to the rod 210 about the longitudinal axis ofthe rod. According to one embodiment, the knob 211 comprises a threadedinner surface suitable for mating the thread of the connecting cap 135.Due to the bearing, the knob 211 of the rod 210 may be screw on theconnecting cap 135 without axial rotation of the rod 210. According toone embodiment, the knob 211 further comprises at the distal end of thethreaded inner surface a protrusion, such as a sawtooth protrusion, or arecess to be engaged in respectively a recess or a protrusion 1352within the connecting cap 135. Thus, once the knob 211 has been screwedonto the connecting cap 135 so that the protrusion 1352 engages therecess, the knob 211 and the connecting cap 135 do not rotateindependently. Thus unscrewing of the knob 211 disengages the connectingcap 135 from the connecting thread 1331.

According to one embodiment, once the protrusion 1352 of the connectingcap engages a recess of the knob 211, the threaded inner surface of theknob 211 depresses the flexible lugs 1351 inside the central opening ofthe sliding ring, so that the sliding ring 131 may be rotated relativeto the drive shaft 133. Consequently, when the knob 211 of the rod 210has been screwed onto the connecting cap 135, the sliding ring 131 canaxially rotate about the longitudinal axis 101 relative to the slidingshaft 132.

According to one embodiment, the deflection plane of the rod 210 may bepre-determined. According to one embodiment, the rod 210 comprises,preferably proximally, at least one key sliding in a keyseat, such as atleast one longitudinal slot, in the internal surface of the drive shaft133. Consequently, the rod 210 is prevented from rotating axiallyrelative to said drive shaft 133. Due to the said key of the rod 210,the deflection plane of the rod 210 may be predefined relative to thedrive shaft 133. According to one embodiment, as the drive shaft 133 isprevented from axially rotating relative to the sliding shaft 132, thedeflection plane of the rod 210 is also predefined relative to thesliding shaft 132 and thus relative to the hub 1322 of the handle; sothat the arrows of the hub 1322 point towards the direction of thepreformed bent of the rod 210.

According to a further aspect of the invention, there is provided asteerable system 300 for creating cavities and injecting material intissue using minimally invasive techniques.

The steerable system 300 according to the invention comprises thesteerable device of the invention and a trocar 310, such as a boneaccess trocar.

According to one embodiment, the trocar 310 extends along a longitudinalaxis 101 from a proximal end 310 a to a distal end 310 b spaced apartfrom the proximal end 310 a along the longitudinal axis 101. Accordingto one embodiment, the length of the trocar 310 along the longitudinalaxis 101 is equal to the length along the longitudinal axis 101 of thefriction reduction cannula 130 from the hub 1322 to the distal end ofthe friction reduction cannula 110 b.

The trocar 310 also defines an outer trocar surface and an inner trocarsurface opposite the outer trocar surface. The inner trocar surfacedefines a trocar opening elongating along the longitudinal axis 101between the distal end 310 b and the proximal end 310 a. According toone embodiment, the trocar opening is configured and sized to receive atleast a portion of the steerable device according to the invention,especially at least a portion of the friction reduction cannula 110.According to one embodiment, the cross-sectional section of the innersurface of the trocar 310 is constant along the longitudinal axis 101.

According to one embodiment, the trocar 310 is connected to the distalend of the handle 130, preferably to the distal end of the sliding shaft132 b, more preferably to the hub 1322. According to one embodiment, thecontrol mechanism 100, especially the friction reduction cannula 110, isinserted in the trocar 310 and the trocar 310 is connected to the distalend of the handle 130, preferably to the distal end of the sliding shaft132 b, more preferably to the hub 1322, by a locking ring 1323.According to one embodiment, the trocar 310 comprises a connectingthread 311 at its proximal end 310 a. The said connecting thread 311 isany connecting thread known by one skilled in the art such as a “luer”type allowing connections of multiple devices equipped with matingthreads According to said embodiment, the trocar 310, especially theconnecting thread 311, is threadedly connected to the distal end of thehandle 130, preferably to the distal end of the sliding shaft 132 b,more preferably to the hub 1322, in a detachable manner.

According to one embodiment, the hub 1322 comprises a locking ring 1323for locking the trocar 310 onto the handle 130. According to oneembodiment, the mating surfaces between the sliding shaft 132 and thetrocar 310 guarantee that the control mechanism 100 is properly locatedonto the trocar 310 both in longitudinal translation and in axialrotation about the longitudinal axis. According to one embodiment, whenthe locking ring 1323 is actuated, there is no degree of freedom betweenthe handle 130 and the trocar 310; the trocar 130 is secured to the hub1322.

According to one embodiment (as explained hereabove), when the frictionreduction cannula 110 is made in a single piece, the friction reductioncannula 110 is secured to the siding shaft 132.

In use, the rod 210 is inserted within the control mechanism 100 withthe handle 130 is in the retracted position. The knob 211 of the rod 210is screwed onto the connecting cap 135. In this position, the rod 210 isin a straight configuration. The control mechanism 100 comprising therod 210 in its retracted position may then be slid through the trocar310 which has been placed in an appropriate location in the patient'stissue. The rod may then be deployed by rotating the sliding ring in thedeployed configuration. In the deployed configuration, the rod 210extends laterally outside of the friction reduction cannula 110 and ofthe trocar 310. Said steps may be repeated with different direction ofthe deflection plane, in order to create multiple interdigitatedcavities. Once the cavities have been created, the rod 210 may beremoved by unscrewing the knob 211 and thus allowing access to theconnecting thread 1331 (the connecting cap 135 being removed with theknob 211). An injection device 320 may then be connected to theconnecting thread 1331 in order to inject material within the createdcavities through the drive shaft 133 and the friction reduction cannula110.

According to one embodiment (as explained hereabove), when the frictionreduction cannula 110 is made in a two parts, the friction reductioncannula 110 is secured with the drive shaft 133.

When the friction reduction cannula 110 comprises a proximal part 111and a distal part 112, the steerable device 110 needs to be armed inorder to bring the distal end of the rod 210 b from a retracted positioninside the proximal part of the friction reduction cannula 111, asdepicted in FIG. 10, to an operational position at the distal end of thedistal part of the friction reduction cannula 112, as depicted in FIGS.5 and 6.

To this end, once the control mechanism 100 comprising the rod 210 isslid through the trocar 310 which has been placed in an appropriatelocation in the patient's tissue and then locked onto the trocar 310,the rod 210 is pushed until the knob 211 comes in contact with theconnecting cap 135. The knob 211 is then screwed on the connecting cap135. As explained hereabove, screwing fully knob 211 onto the connectingcap 135, protrusion or recess of the knob 211 engages respectively arecess or protrusion 1352 of the connecting cap 135, thus locking theknob 211 on the connecting cap 135. Screwing fully knob 211 onto theconnecting cap 135 also pushes inwards the flexible lugs 1351, freeingthem from the corresponding openings in the proximal end of the slidingring 131 a, thus allowing rotation of the sliding ring 131.

According to one embodiment, when the distal end of the threaded innersurface of the sliding ring 131 engages with the protrusion(s) 1321 ofthe sliding shaft 132 (retracted position), and when the steerabledevice is secured to the trocar 310, the translation of the drive shaftto the deployed position caused by the rotation of the sliding ring 131drives both the friction reduction cannula 110 and the rod 210 toextends out of the trocar laterally, thus creating a cured cavity in thetissue, as depicted in FIGS. 7 and 8.

Once the cavity has been created, the rod 210 may be removed byunscrewing the knob 211 and thus allowing access to the connectingthread 1331 (the connecting cap 135 being removed with the knob 211). Aninjection device may then be connected to the connecting thread 1331 inorder to inject material within the created cavities through the driveshaft 133 and the friction reduction cannula 110, as depicted in FIGS.13, 14 and 15. Due to the flexible part of the friction reductioncannula 112 and by rotating the handle from the deployed position to theretracted position, material may be injected in a retrograde manner.

According to one embodiment, the material may be any material known toone skilled in the art, such as bone cement.

While various embodiments have been described and illustrated, thedetailed description is not to be construed as being limited hereto.Various modifications can be made to the embodiments by those skilled inthe art without departing from the true spirit and scope of thedisclosure as defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

As explained in the specification hereabove, FIGS. 1 to 15 relate to acontrol mechanism, a steerable device and a steerable system wherein thefriction reduction cannula comprises a distal part and a proximal partand is connected to the drive shaft. FIGS. 16 to 18 relate to a controlmechanism, a steerable device and a steerable system wherein thefriction reduction cannula is made of a single piece and is connected tothe sliding shaft.

FIG. 1 is a front view of the control mechanism according to oneembodiment of the invention.

FIG. 2 is a front view of the steerable system with the controlmechanism in the retracted position according to one embodiment of theinvention, without the rod.

FIG. 3 is a sectional view of the steerable system of FIG. 2 along planeAA.

FIG. 4 is a sectional view of FIG. 2 along plane BB.

FIG. 5 is a front view of the steerable system with the controlmechanism in the armed position according to one embodiment of theinvention.

FIG. 6 is a sectional view of the steerable system of FIG. 5 along planeAA.

FIG. 7 is a front view of the steerable system with the controlmechanism in the deployed position according to one embodiment of theinvention.

FIG. 8 is a sectional view of the steerable system of FIG. 7 along planeAA.

FIG. 9 is a sectional view of the steerable system of FIGS. 5 and 7along plane BB.

FIG. 10 is a front view of the steerable device in the retractedposition according to one embodiment of the invention.

FIG. 11 is a sectional view of the steerable device according to FIG. 10along plane AA.

FIG. 12 is a sectional view of the steerable device of FIG. 10 alongplane BB.

FIG. 13 is a front view of the steerable system with the controlmechanism connected with an injection device.

FIG. 14 is a sectional view of the steerable system of FIG. 13 alongplane AA.

FIG. 15 is a sectional view of FIG. 13 along plane BB.

FIG. 16 is a front view of the steerable system with the controlmechanism in the retracted position according to one embodiment of theinvention, without the rod.

FIG. 17 is a sectional view of the steerable system of FIG. 16 alongplane AA.

FIG. 18 is a sectional view of FIG. 16 along plane BB.

REFERENCES

-   100—Control mechanism;-   100 a—Proximal end of the control mechanism;-   100 b—Distal end of the control mechanism;-   101—Longitudinal axis of the control mechanism;-   110—Friction reduction cannula;-   110 a—Proximal end of the friction reduction cannula;-   110 b—Distal end of the friction reduction cannula;-   111—Proximal part of the friction reduction cannula;-   112—Distal part of the friction reduction cannula;-   130—Handle;-   131—Sliding ring;-   131 a—Proximal end of the sliding ring;-   131 b—Distal end of the sliding ring;-   132—Sliding shaft;-   132 a—Proximal end of the sliding shaft;-   132 b—Distal end of the sliding shaft;-   1321—Protrusion of the sliding shaft;-   1322—Hub;-   1323—Locking ring;-   133—Drive shaft;-   133 a—Proximal end of the drive shaft;-   133 b—Distal end of the drive shaft;-   1331—Connecting thread;-   135—Connecting cap;-   1351—Flexible lug;-   1352—Protrusion;-   200—Steerable device;-   210—Rod;-   210 a—Proximal end of the rod;-   210 b—Distal end of the rod;-   211—Knob of the rod;-   300—Steerable system;-   310—Trocar;-   310 a—Proximal end of the trocar;-   310 b—Distal end of the trocar;-   311—Connecting thread;-   320—Injection device.

The invention claimed is:
 1. A control mechanism for controlling a rodhaving a preformed bend and at least one key, the control mechanismcomprising: a handle comprising a sliding ring, a sliding shaft and adrive shaft comprising an internal surface defining at least onelongitudinal groove or keyseat configured to engage the at least one keyof the rod, each of the sliding ring, the sliding shaft, and the driveshaft extending along a longitudinal axis, wherein the sliding ring isthreadedly connected to the sliding shaft; blocking means which preventaxial rotation between the drive shaft and the sliding shaft and whichallow the drive shaft to slide within the sliding shaft; connectingmeans which prevent axial displacement between the drive shaft and thesliding ring and which allow axial rotation between the drive shaft andthe sliding ring; and a friction reduction cannula configured to receivethe rod, wherein the friction reduction cannula is secured to thesliding shaft or to the drive shaft.
 2. The control mechanism accordingto claim 1, wherein the sliding ring comprises a threaded inner surfaceand the sliding shaft comprises at least one protrusion protrudingoutwardly from the sliding shaft and engaging the at least one threadedinner surface of the sliding ring so that axial rotation of the slidingring causes the sliding shaft to move back and forth along thelongitudinal axis.
 3. The control mechanism according to claim 1,wherein the blocking means comprise at least one key or at least onelongitudinal keyseat within an external surface of the drive shaftengaged respectively with at least one longitudinal keyseat or at leastone key within the internal surface of the sliding shaft.
 4. The controlmechanism according to claim 1, wherein the connecting means between thedrive shaft and the sliding ring comprise a bearing.
 5. The controlmechanism according to claim 1, wherein the friction reduction cannulahas a longitudinal axis and comprises an opening configured to receiveand restrain at least the preformed bend of the rod in a straightconfiguration along the longitudinal axis.
 6. The control mechanismaccording to claim 5, wherein the friction reduction cannula comprises aproximal part and a distal part, wherein the distal part is moreflexible than the proximal part so that the proximal part restrains therod the straight configuration and the distal part does not restrain therod in the straight configuration.
 7. The control mechanism according toclaim 1, wherein the drive shaft further comprises at its proximal end aconnecting thread.
 8. The control mechanism according to claim 7,further comprising a connecting cap comprising a threaded inner surfaceassembled onto the connecting thread, the connecting cap comprising aplurality of flexible lugs protruding distally and outwardly andconfigured to engage a plurality of openings at or near a proximal endof the sliding ring thereby preventing rotation of the sliding ring. 9.A steerable device comprising a control mechanism according to claim 1,wherein the rod comprises a superelastic material.
 10. The steerabledevice according to claim 9, wherein the rod comprises at its proximalend a knob comprising a threaded inner surface configured to beassembled onto a connecting cap, the knob and the rod being connected bya bearing which allow axial rotation between the knob and the rod.
 11. Acontrol mechanism for controlling a rod having a preformed bend, thecontrol mechanism comprising: a handle comprising a sliding ring, asliding shaft and a drive shaft, each of the sliding ring, the slidingshaft, and the drive shaft extending along a longitudinal axis, whereinthe sliding ring is threadedly connected to the sliding shaft; whereinone of the drive shaft and the sliding shaft comprises at least onekeyseat and the other one of the drive shaft and the sliding shaftcomprises a key configured to slidably move within the at least onekeyseat such that axial rotation is blocked between the drive shaft andthe sliding shaft and slidable movement of the drive shaft relative tothe sliding shaft is allowed; a bearing operably connecting the driveshaft and the sliding ring and configured to prevent axial displacementbetween the drive shaft and the sliding ring and allow axial rotationbetween the drive shaft and the sliding ring; and a friction reductioncannula configured to receive the rod; wherein the friction reductioncannula is secured to the sliding shaft or to the drive shaft.
 12. Thecontrol mechanism according to claim 11, wherein the sliding ringcomprises a threaded inner surface and the sliding shaft comprises atleast one protrusion protruding outwardly from the sliding shaft andengaging the at least one threaded inner surface of the sliding ring sothat axial rotation of the sliding ring causes the sliding shaft to moveback and forth along the longitudinal axis.
 13. The control mechanismaccording to claim 11, wherein the friction reduction cannula has alongitudinal axis and comprises an opening configured to receive andrestrain at least the preformed bend of the rod in a straightconfiguration along the longitudinal axis.
 14. The control mechanismaccording to claim 13, wherein the friction reduction cannula comprisesa proximal part and a distal part, wherein the distal part is moreflexible than the proximal part so that the proximal part restrains therod in the straight configuration and the distal part does not restrainthe rod in the straight configuration.
 15. The control mechanismaccording to claim 11, wherein the drive shaft further comprises at aproximal end a connecting thread.
 16. The control mechanism according toclaim 15, further comprising a connecting cap comprising a threadedinner surface assembled onto the connecting thread, the connecting capcomprising a plurality of flexible lugs protruding distally andoutwardly and configured to engage a plurality of openings at or near aproximal end of the sliding ring thereby preventing rotation of thesliding ring.